Click here to listen to the audio.
 

By Robin Jay, Editorial Director

Coffee lovers everywhere know what the consequences can be if they skip their morning cup of joe – a throbbing headache, fatigue and difficulty concentrating, to name a few. Stacey Sigmon, Ph.D., research associate professor of psychiatry at the University of Vermont College of Medicine and colleagues at Johns Hopkins School of Medicine sought to investigate the biological mechanisms of caffeine withdrawal in a paper published recently in the online edition of the scientific journal Psychopharmacology. The researchers goal was to understand the mechanism in the brain that causes the typical caffeine withdrawal headache. The studies produced a provocative and unexpected finding that will surprise you: The "pick-me-up" effect of caffeine is temporary. You may not realize it, but after a few weeks, drinking coffee no longer gives you the lift it once did. So what really keeps coffee drinkers drinking coffee? The need to avoid withdrawal symptoms. Dr. Sigmon joins us today to talk about this intriguing finding.

BHC: Dr. Sigmon, thank you for joining us.

Stacey Sigmon: Sure. A number of prior studies have demonstrated that with abrupt cessation of caffeine use, people experience a number of subjective effects: sleepiness, fatigue, headache, etc. but few studies had really looked at, in a very controlled, rigorous manner, the kind of underlying biological mechanisms of caffeine withdrawal. So we wanted to find out what was really going on in the brain that is interpreted as tiredness, fatigue, lethargy, headache. We conducted a double-blind lab study at Johns Hopkins to really examine in the most rigorous manner yet the underlying biological mechanisms of caffeine withdrawal. We evaluated three different measures – brain electrical activity, measured that via EEG; and then blood flow velocity in the brain, so that was measured by Doppler ultrasound (and that’s just the blood flow velocity in the blood vessels in the brain) and then just patient self reports of objective effects by questionnaires.

In the lab study basically people were maintained for at least three weeks on either caffeine, a steady dose of caffeine or placebo, and all of the caffeine and placebos were administered in gel capsules, so completely double-blind, neither the participants or the staff knew what ones were being received on a given day. There were no beverages consumed, people weren’t consuming caffeine in any other parts of their diet, so it’s a very rigorous study. They were maintained on caffeine for two or three weeks and then they had challenge sessions in which they received acute placebo or acute caffeine and then, after that, they alternate to a chronic placebo phase – so no longer ingesting any form of caffeine for two to three weeks. Then they have two similar challenge sessions of caffeine and placebo.

But one of the primary areas of the study was during that chronic caffeine maintenance phase and then during the placebo challenge day, which occurred during the chronic caffeine maintenance. We studied what goes on in the brain when you basically take a regular caffeine consumer, someone who’s ingesting these caffeine capsules every day and then switches out a placebo dose (basically an acute caffeine abstinence). We did this to characterize withdrawal that occurs during acute caffeine abstinence in the brain and then to subjective effects. That was the primary focus of study.

When we did that, we found a few interesting and expected things. We saw that the blood flow velocity significantly increased (and that’s typically a marker that explains the headache). That kind of showed the underlying physiological mechanism behind that common classic headache. Increased EEG theta power, which is associated or interpreted as increased drowsiness; decreased beta power on the EEG, that’s typically interpreted as decreased alertness; and then the whole constellation of subjective effects that we would expect to see: increased ratings of tired, fatigue, sluggishness and weariness and decreased ratings of energetic, friendly, liveliness and vigor.

So not that these things are unexpected, but they really represented the most rigorous evaluation to date of what’s going on physiologically during abrupt cessation of caffeine. And again, done in the most rigorous way to date; double-blind and the study design itself took a lot of various controls. We did saliva testing to ensure they weren’t consuming other forms of caffeine and very lengthy maintenance phases of both placebo and caffeine (that’s been a weakness of prior studies.) So in all ways, this was the most rigorous test to date.

Then in the secondary finding, kind of the more unexpected finding, was a product that was kind of unique. The various controls, the lengthy maintenance phases, etc. that we used in the study design were to evaluate withdrawal, but they also provided a unique opportunity to examine the effects of acute caffeine abstinence. So if you think about it, for half of their time on the study, people were maintained on caffeine and got those challenge sessions, but for a few more weeks, they were maintained on placebo, during which they also had an acute caffeine. And what we unexpectedly found is that there were no significant differences between the caffeine maintenance phase and the placebo maintenance phase on blood flow velocity in the brain, electrical activity in the brain, and subjective effects. That was surprising because most of us coffee lovers would think that we were still getting some benefits. Why else would we be drinking caffeine every day?

We’re still getting some degree of improved alertness, attention or energy, but the lack of significant differences on these measures between these two maintenance phases told us that there’s no evidence of net beneficial effects associated with habitual caffeine administration. If you are not a caffeine drinker and you begin drinking coffee, you may get some “bang for your buck” in the first several days, but once you essentially develop some tolerance to the effects, and are ingesting caffeine regularly, those that we would perceive as beneficial effects probably go away and you just now are maintained on something. We may just be drinking it to avoid the withdrawal, to avoid the headache that happens if you abruptly stop, rather than truly continue to get benefits with ongoing ingestion.

BHC: That is just amazing! When the study participants were on the placebos, did they know that that was a placebo phase or did they think that they were still on the caffeine?

SS: No one knew when they were getting placebo, when they were getting caffeine; they never knew when a challenge day is a challenge day. They knew overall that the study is evaluating people’s response to placebo, different stimulants, different medications, but they don’t even know that the study is primarily interested in caffeine. They could not be consuming caffeine in their diet, we did saliva samples to check that, but we didn’t tell them ‘don’t drink caffeine’ because then it would defeat the purpose of it being a double blind test. So we gave them a list of dietary restrictions of which (caffeinated) foods and beverages they couldn’t have, but we took care to include other items that help to ensure that the participants are not aware of that caffeine is even the focus of the experiment. So a lot of was taken to ensure no one had any expectations or biases.

BHC: Is there any recommendations as a result of these findings?

SS: Yes. I mean certainly in terms of the withdrawal, that’s a primary aim, so we replicated the acute withdrawal symptoms that would occur with abrupt cessation. So in that sense, the take-home message for that would be to taper off slowly. Taper down a little more gradually over a few days instead of all at once and that would help you avoid the headache and such. And in terms of the net beneficial effects, if you really wanted to be strategic about your coffee drinking and make sure you’re getting the “bang for your buck,” I guess you can cycle back and forth between regular coffee and no coffee or regular and decaf, so for a week you’d enjoy the effects and then once they plateau, you work your way down to nothing or to decaf, and then work your way back up. Will most of us take care to do that, I don’t know.

Comments (0)

Subscribe to this comment's feed